Cable stripping tool

ABSTRACT

A cable stripping tool comprising clamp means having a pair of jaws adapted to close onto a cable for permitting stripping of the sheathing from the cable. A cutter element is mounted on one of the clamp jaws and is positioned to penetrate the sheathing upon closure of the jaws. The cutter causes a helical strip to be severed from the cable sheathing by rotating the clamp means around the cable. The cutter element preferably lies in a general plane which is longitudinal to but slightly offset from the central axis of the cable. The general plane of the blade is preferably slightly inclined at a small angle to the cable axis.

( 1 Aug. 29, 1972 United States Patent Bull 2,902,759 9/1959Miller.........................30/90.2

[54] CABLE STRIPPING TOOL [72] Inventor: Victor Edward Bull, 28 UnionSt.,

Northcote, Victoria, Australia Prlmary Examme" Rben Rlordo Feb. 18, 1970[21] Appl.No.: 12,419

Assistant Examiner-Roscoe V. Parker, Jr.

[22] Filed:

Attorney-Woodhams, Blanchard-and Flynn ABSTRACT A cable stripping toolcomprising clamp means having a pair of jaws'adapted to close onto acable for permitting stripping of the sheathing from the cable. A

cutter element is mounted on one of the clamp jaws itioned to penetratethe sheathing upon clojaws. The cutter causes a helical strip to besevered from the cable sheathing by rotating the clamp means around thecable. The cutter element lies in a general plane which is longitudinaltly offset from the central axis of the cable.

general plane of the blade is preferably slightly inclined at a smallangle to the cable axis.

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CABLE STRIPPIN G TOOL BACKGROUND OF INVENTION 1. Field of Invention Thisinvention provides a novel form of cable stripping tool, i.e., a toolfor the purpose of stripping sheathing from electric cable. Thesheathing of the cable bay be comprised entirely of an insulatingmateria1 or it may be of the king having a soft metal outer casmg.

2. Brief Description of Prior Art There are known forms of cablestripping tool comprising a cutter blade which in operation of the toolcuts a helical strip of sheathing from the cable to expose the core ofthe cable. However all previously known tools of this type have onlyproved satisfactory for stripping from a cable end and they have been ofno use in cases where cable must be stripped at locations remote fromits ends.

When erecting overhead electric cable, of the insulated type the cablemust be stripped at regular intervals along its length and, in theabsence of a satisfactory stripping tool, this is generally done at thepresent time by cutting with a sharp knife. This is not only laboriousbut also an extremely dangerous operation.

SUMMARY OF THE INVENTION The present invention provides an improvedstripping tool which can be operated quickly and safely to stripsheathing from a cable at a location remote from its ends. In itspreferred form, the tool can be operated to strip the sheathing betweenprecise predetermined limits and with cut edges exactly perpendicular tothe longitudinal axis of the cable.

The cable stripping tool of the invention comprises a clamp which has apair of jaws and is hand operable to close the jaws onto a cable to bestripped of sheathing, and, mounted on the clamp, a cutter element whichis so shaped and positioned that on closing of the jaws onto the cableit penetrates the sheathing of the cable and can then be caused to severa helical strip from the cable sheathing by rotating the clamp aroundthe cable.

Preferably the cutter element is formed by a blade which, when itpenetrates the sheathing, lies in a general plane which is longitudinalto the cable and is offset from the central axis of the cable..Althoughextending longitudinally of the cable, the general plane of the blademay be, and preferably is, inclined at a slight angle to the cable axis.

Preferably further, the blade has an inner end (with respect to thecable) which is generally saw-tooth shaped to facilitate penetration ofthe cable sheathing.

In order that the invention may be more fully explained, two particularembodiments thereof will now be described in detail with reference tothe accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS In the drawings:

FIG. 1 is a perspective view of one form of cable stripping tooloperating to strip a cable;

FIG. 2 is a side elevation of the tool with its clamp jaws in an opencondition;

FIG. 3 is a plan of the tool of FIG. 1;

FIG. 4 is a cross-section on the line 4-4 in FIG. 3;

FIG. 5 is a cross section on the line 5-5 in FIG. 3;

FIG. 6 is a cross-section on the line 66 in FIG. 5;

FIG. 7 is a cross-section generally on the line 7-7 in FIG. 5;

FIG. 8 is a perspective view of a cutter blade fitted to the tool ofFIGS. 1 to 7;

FIGS. 9 and 10 are diagrammatic cross-sections illustrating the mannerin which the tool can accommodate a wide variation of cable sizes;

FIG. 11 is an elevation of an alternative form of cable stripping toolconstructed in accordance with the invention; and

FIG. 12 is a cross-section on the line 12-12 in FIG.

DESCRIPTION OF PREFERRED EMBODIMENTS The stripping tool illustrated byFIGS. 1 to 10 comprises a hand operable jaw clamp denoted generally as13, which is fitted with a cutter blade 14. Clamp 13 is of the type wellknown as a toggle clamp. It comprises a pair of V-shaped jaws 15, 16which can be closed onto a cable 17 by swinging a movable hand gripportion 18 from the position shown in FIG. 2 toward a fixed hand gripportion 19.

Hand grip portion 19 is formed by an end of a long lever 21 the otherend of which carries the jaw 16. .law 15 is carried by a channel-shapedstructure 22 which is pivotally connected to lever 21 by a pivot bolt23. Hand grip portion 18 pivots about a pivot bolt 24 which is carriedby a slide 26 fitted in a slot 27 in structure 22. A toggle bar 28 ispivotally connected at one end to hand grip portion 18 by pivot bolt 29and it is pivotally connected at its other end to the outer end of handgrip portion 19 by means of a further pivot bolt 31. The arrangement issuch that the clamp moves from the open condition of FIG. 2 to itsclosed condition (best seen in FIGS. 1 and 4) with an over-center actionso that it will remain in the closed condition. A screw-threaded stem 32extends from slide 26 to engage an internally threaded adjustment wheel33 disposed in a slot 34 in the top of structure 22. Rotation of theadjustment wheel 33 moves the position of pivot bolt 24 by motion of theslide 26 along slot 27 whereby to vary the spacing of the closedposition of jaws l5, 16 to suit the size of cable to be stripped. Aresilient spring 36 located on pivot pin 23 acts between lever 21 andthe serrated rim of wheel 33 to maintain the setting of the adjustmentwheel.

One of the legs of the movable jaw 15 is recessed at 37 to enable thecutter blade 14 to project into the bight of jaw 15 and toward jaw 16.Cutter blade 14 is formed from a strip of tool steel and it is firmlyfastened to a grooved channel-shaped member 38 formed integrally withjaw 15 and welded to the structure 22. The blade has slots 39, 41 and itis located in groove 42 of member 38 and firmly held in position byclamping means in the form of a clamping bolt 44 which extends throughslot 41 to engage a clamping block 46. Tightening of clamping bolt 44draws clamping block 46 firmly against the front face 40 of the blade.The blade can be positioned longitudinally of groove 42 by rotation of aslotted head 43 which is mounted eccentrically on a pin 45 and engagesthe slot 39 in the blade.

Blade 14 is set so that its general plane extends longitudinally of jaw15 but is offset from a longitudinal plane through the apex or root ofthat jaw. Its inner edge which projects into the bight of jaw 15 isshaped generally to a saw-tooth having an inner tip 47. The

short or steep" side of the saw-tooth is defined by a single straightside edge 48 whereas the longer or shallow side is defined by twostraight edge portions 49 and 50 which are slightly inclined to oneanother. The

front face 40 of cutter blade 14 is planar right through to tip 47whereas the rear of the blade is relieved so that inclined relief faces51, 52, 53 extend back from cutting edges 48, 49 and 50 respectively.

In order to strip the cable 17 at a location between its ends theclampjaws are firstly closed onto the cable at the required location. Asthe jaws close ontothe cable the inner tip 47 of cutter blade 14penetrates the sheath 54 of the cable. The geometry of the jaws and theblade is such that the closing action of the jaws causes-the inner endofthe cutter blade to penetrate the sheath of the cable. The general planeof the blade 6 then extends longitudinally of the cable and is off-setslightly from the central axis of the cable. It is almost parallel witha diametral plane of the cable but as will be appreciated from FIGS. 2to 7 it in fact subtends a very slight angle to that plane and thereforeto the axis of the cable. The geometry is such that the tip 47 of theblade just clears the central core 56 of the cable.

The clamp is now rotated around the cable in the direction shown by thearrows in FIGS. 1, and 7, i.e., so that the inner tip 47 leads theremainder of the cutter blade and the planar front face of the bladeleads the relieved rear of the blade. This rotation causes that part ofthe sheathing in front of the buried part of the cutter blade to bepeeled back against the front face 40 of the blade and the sides of thisportion are severed by the edges 48 and 50 of the blade. At the start ofthe rotation only the lower part of the saw-tooth end of the bladeextends into the insulation. Therefore, at first only a narrow portionof insulation is peeled. However this quickly widens as more of edge 50feeds into the insulation due to the slight inclination of the blade tothe longitudinal diametral plane of the cable. By continuing therotation of the clamp and feeding-it along the cable at the stem at thesame time a helical strip 57 of the sheathing can be peeled from thecable to expose the core. FIG. 1 shows an exposed length of the core 56and the cut edge 58 of insulation where the cutter blade firstpenetrated the sheath.

FIGS. 5 and 7 show the manner in which the blade strips back theinsulation into the helical strip 57. The

stripping action is very clean. Because the blade 14 is fed into theinsulation material face on with its lower end leading, it provides awedging action which lifts the insulation away from the core 56. Thuseven though tip 47 may be some distance out from the core the insulationwill be removed cleanly from the core and severed.

It has been found in practice that the tool can be used satisfactorilywith cables of greatly differing sizes without altering the setting ofthe cutter blade 14. The only adjustment required is to alter thesetting of the clamp jaws by means of wheel 33. FIGS. 9 and 10illustrate diagrammatically the manner in which the tool can be closedonto two different cables 59, 60 of widely differing sizes. It will beseen in both cases the penetration of cutter blade 14 is such that itstip 47 lies immediately outside the core of the cable.

FIGS. 11 and 12 illustrate a different form of cable stripping toolconstructed in accordance with the invention. This tool utilizes a clampwhich is different from the toggle clamp of the previous embodiment butit has a pair of clamp jaws and a cutter blade which are identical tothose of the previous embodiment and which are identified by likereference numerals. In this case the clamp jaws are mounted on a pair ofclamp levers 61, 2 which are pivotally connected by a pivot pin 63.These levers can be swung toward one another by rotation of a knurledclamping nut 64 mounted on a bolt 66 which extends through holes in aflange 67 on lever 61 and a flange 68 on lever 62. The levers movetogether against the action of a biasing spring 69 disposed around bolt66 to act between the flanges 67,

68 and thereby to provide an opening bias force.

The geometry of the jaws and the blade is precisely the same as in theprevious embodiment so that when the jaws are closed onto a cable theblade penetrates the sheath in much the same manner. The tool is thenrotated about the cable and it peels a helical strip of insulation fromthe cable in much the same manner as the previous embodiment. 1 7

Although the illustrated tools have proved to be most satisfactory inservice it is to be understood that these tools have been advanced byway of example only. The invention is in no way limited to theseparticular constructions but may include many modifications andvariations within its spirit and scope.

I claim:

I 1. A stripping tool for permitting sheathing to be stripped from acable, comprising:

clamp means including a pair of relatively pivotable clamping jawsoperable to close onto a cable to permit sheathing to be strippedtherefrom;

- cutter blade means, said cutter blade means being mounted on andfixedly secured to one of said jaws and opposing the other of said jawswhereby the cutting edge of said cutter-blade means simultaneouslypenetrates the sheathing when the jaws are moved into said closedposition in surrounding relationship to said cable; and

means mounting said cutter blade means on said clamp means forpositioning said cutter blade means in a general plane which in onedirection is substantially longitudinal to the cable, which is offsetlaterally relative to the longitudinal axis of the cable, and which isaligned in a direction substantially transverse to said one directionwith the direction of relative closing movement between the jaws suchthat an inner end of the cutter blade means simultaneously penetratesthe sheathing ofv the cable upon closing of the jaws onto the cable,said inner end of the cutter blade means having a substantially planarface positioned remote from the cable axis and bounded at one side by aside edge whereby, by rotation of the tool about the cable with saidplanar face of the cutter blade means leading in the direction ofrotation, saidside edge can sever a helical strip of cable sheathingwhich strip is peeled back from the cable by engagement with said planerface.

2. A tool according to claim 1, wherein the general plane of the cutterblade means is inclined at a small acute angle relative to the cableaxis.

3. A tool according to claim 1, wherein the cutting edge of the cutterblade means is generally of a sawtooth shape to facilitate penetrationof the cable sheathing, said cutter blade means being initially setrelative to said clamp means so that only a tip portion of the saw toothpenetrates the sheathing upon closing of the clamp jaws onto the cablebut on rotation of the tool about the cable a widening strip is cut bythe sides of the saw-tooth shaped edge.

4. A stripping tool for permitting sheathing to be stripped from acable, comprising:

clamp means including a pair of relatively movable clamping jawsoperable to close onto a cable to permit sheathing to be strippedtherefrom;

cutter blade means mounted on said clamp means for penetrating thesheathing of the cable upon closing of the jaws onto the cable, saidblade means comprising a cutter blade having a cutting edge which isgenerally of a saw-tooth shape to facilitate penetration of the cablesheathing;

said cutter blade being disposed in a general plane which islongitudinal to the cable but is offset laterally relative to thelongitudinal axis of the cable, said cutter blade having a side edge forsevering the sheathing and a leading face for peeling back the severedstrip of cable sheathing upon rotation of the too] about the cablewhereby the tool severs a helical strip of sheathing from the cable;

said cutter blade being initially set relative to said clamp means sothat only a tip portion of the saw tooth penetrates the sheathing uponclosing of the clamp jaws onto the cable but on rotation of the toolabout the cable a widened strip is cut by the sides of the saw-toothsharpened edge; and

I the cutting edge of said blade being substantially planar on theleading face thereof whereas the reverse face of the cutting edge isdefined by inclined relief faces, said leading face being positionedremote from the cable axis.

5. A tool according to claim 1, wherein said cutter blade meanscomprises a platelike member having an elongated cutting edge along oneedge thereof, said cutting edge extending substantially longitudinallyof said cable and being adapted to contact and penetrate said sheathingsubstantially longitudinally of said cable. 6. A stripping tool forpermitting sheathing to be stripped from a cable, comprising:

clamp means including a pair of relatively movable clamping jawsoperable to close onto a cable to permit sheathing to be strippedtherefrom; said clamp means including first and second lever memberseach having a clamping jaw thereon with said jaws being disposedsubstantially opposite one another when said lever members are moved toa closed position to position said jaws in engagement with a cable, andpivot means coacting between said lever members for permitting relativepivotal movement thereof between opened and closed positions;

cutter blade means mounted on said clamp means for penetration of thesheathing of the cable upon closing of the "jaws onto the'cable, saidblade means comprising a cutter blade disposed in a general plane whichis longitudinal to the cable but is offset laterally relative to thelongitudinal axis of thereof, said elongated cutting edge extendingsubstantially longitudinally of said cable when said jaws are moved intosaid closed position, and adjustment means coacting between said cuttingblade and its respective jaw for permitting the position of said cuttingblade to be selectively varied relative to said jaw.

1. A stripping tool for permitting sheathing to be stripped from acable, comprising: clamp means including a pair of relatively pivotableclamping jaws operable to close onto a cable to permit sheathing to bestripped therefrom; cutter blade means, said cutter blade means beingmounted on and fixedly secured to one of said jaws and opposing theother of said jaws whereby the cutting edge of said cutter blade meanssimultaneously penetrates the sheathing when the jaws are moved intosaid closed position in surrounding relationship to said cable; andmeans mounting said cutter blade means on said clamp means forpositioning said cutter blade means in a general plane which in onedirection is substantially longitudinal to the cable, which is offsetlaterally relative to the longitudinal axis of the cable, and which isaligned in a direction substantially transverse to said one directionwith the direction of relative closing movement between the jaws suchthat an inner end of the cutter blade means simultaneously penetratesthe sheathing of the cable upon closing of the jaws onto the cable, saidinner end of the cutter blade means having a substantially planar facepositioned remote from the cable axis and bounded at one side by a sideedge whereby, by rotation of the tool about the cable with said planarface of the cutter blade means leading in the direction of rotation,said side edge can sever a helical strip of cable sheathing which stripis peeled back from the cable by engagement with said planer face.
 2. Atool according to claim 1, wherein the general plane of the cutter blademeans is inclined at a small acute angle relative to the cable axis. 3.A tool according to claim 1, wherein the cutting edge of the cutterblade means is generally of a saw-tooth shape to facilitate penetrationof the cable sheathing, said cutter blade means being initially setrelative to said clamp means so that only a tip portion of the saw toothpenetrates the sheathing upon closing of the clamp jaws onto the cablebut on rotation of the tool about the cable a widening strip is cut bythe sides of the saw-tooth shaped edge.
 4. A stripping tool forpermitting sheathing to be stripped from a cable, comprising: clampmeans including a pair of relatively movable clamping jaws operable toclose onto a cable to permit sheathing to be stripped therefrom; cutterblade means mounted on said clamp means for penetrating the sheathing ofthe cable upon closing of the jaws onto the cable, said blade meanscomprising a cutter blade having a cutting edge which is generally of asaw-tooth shape to facilitate penetration of the cable sheathing; saidcutter blade being disposed in a general plane which is longitudinal tothe cable but is offset laterally relative to the longitudinal axis ofthe cable, said cutter blade having a side edge for severing thesheathing and a leading face for peeling back the severed strip of cablesheathing upon rotation of the tool about the cable whereby the toolsevers a helical strip of sheathing from the cable; said cutter bladebeing initially set relative to said clamp means so that only a tipportion of the saw tooth penetrates the sheathing upon closing of theclamp jaws onto the cable but on rotation of the tool about the cable awidened strip is cut by the sides of the saw-tooth sharpened edge; andthe cutting edge of said blade being suBstantially planar on the leadingface thereof whereas the reverse face of the cutting edge is defined byinclined relief faces, said leading face being positioned remote fromthe cable axis.
 5. A tool according to claim 1, wherein said cutterblade means comprises a platelike member having an elongated cuttingedge along one edge thereof, said cutting edge extending substantiallylongitudinally of said cable and being adapted to contact and penetratesaid sheathing substantially longitudinally of said cable.
 6. Astripping tool for permitting sheathing to be stripped from a cable,comprising: clamp means including a pair of relatively movable clampingjaws operable to close onto a cable to permit sheathing to be strippedtherefrom; said clamp means including first and second lever memberseach having a clamping jaw thereon with said jaws being disposedsubstantially opposite one another when said lever members are moved toa closed position to position said jaws in engagement with a cable, andpivot means coacting between said lever members for permitting relativepivotal movement thereof between opened and closed positions; cutterblade means mounted on said clamp means for penetration of the sheathingof the cable upon closing of the jaws onto the cable, said blade meanscomprising a cutter blade disposed in a general plane which islongitudinal to the cable but is offset laterally relative to thelongitudinal axis of the cable, said cutter blade means having a sideedge for severing the sheathing and a leading face for peeling back thesevered strip of cable sheathing upon rotation of the tool about thecable whereby the tool severs a helical strip of sheathing from thecable; and said cutter blade being mounted on and fixedly secured to oneof said jaws whereby the cutting edge of said blade automaticallypenetrates the sheathing when the jaws are moved into said closedposition in surrounding relationship to the cable.
 7. A tool accordingto claim 6, wherein said cutting blade comprises a substantiallyplatelike member having an elongated cutting edge formed on one edgethereof, said elongated cutting edge extending substantiallylongitudinally of said cable when said jaws are moved into said closedposition, and adjustment means coacting between said cutting blade andits respective jaw for permitting the position of said cutting blade tobe selectively varied relative to said jaw.